In his words, more than 826,000 litas (EUR 239,400) from the bookkeeping fraud could have been spent on the elections.
"There is no evidence of (the party's leader Viktor) Uspaskich spending his personal money, there is data showing that it came from black bookkeeping," the prosecutor said.
Verseckas of the Prosecutor General's Office did not finish his closing argument on Friday. He is expected to propose punishments for the Labor Party and its leaders in three weeks, on May 24.
The prosecutor maintains that Uspaskich has seen the fraud books.
The Labor Party is charged with failing to include more than 24 million litas in income and 23 million litas in spending into its books between 2004 and 2006.
The Labor Party's members strongly deny the accusations, saying the case is politically-motivated. The case reached court back in 2008.